What You Should Know About Flat Roof Solar Panels

What You Should Know About Flat Roof Solar Panels

Solar power is becoming one of the main solutions for today’s energy crisis in many countries. As solar power becomes more popular and advance many solar applications have been introduced to the market. Solar power is used to power up many residential and commercial properties. Solar energy is a clean, free, and renewable energy source. So many people like to use it to save both money and the environment.  When it comes to the home solar systems most solar panels are placed on the roof. We cannot expect that all the roofs to be sloped roofs. There are flat roofs as well. Especially in commercial buildings, most roofs are flat. So by this article, We would like to cover important facts about the flat roof solar panels.

Flat roof solar panels and systems are the same as other solar panels in structure. Only the installation process and the maintenance will be different from the sloped roofs. The installation process is easier with flat roof solar panels but you may need some special installation systems to place the solar panels properly fixed to the location of the roof. As the installation process and equipment are different from standard ways many solar installation companies do not install flat roof solar even though the installation process is easier. This is mainly to minimize the cost. When it comes to maintenance flat roofs and flat roof solar panels require more maintenance than sloped roofs and solar systems.

Can you install solar panels on a flat roof?

Yes, you can install solar panels on flat roofs. Installing solar panels or solar systems on a flat roof is easier and cheaper. Even though there are some limitations flat roof also an ideal location to install a solar system. Flat roofs offer more flexibility when installing solar panels. Even though the solar panels work under indirect sunlight, direct sunlight is best for the panels. As we can place the panels in any direction we can place the panels at the optimum direction to maximize the amount of sunlight received by panels.

Why is it easy to install solar panels on flat roofs

Why is it easy to install solar panels on flat roofs


Flat roofs are easier to access. Unlike on sloped roofs, workers do not need any special gear to work on flat roofs. They do not have to hang on using cables as flat roofs are easier and safer to move around. So the labor cost for a flat roof is cheaper.

Flat roof solar panels are free-standing solar panels. So you do not have to worry about drilling holes onto your roofs. But if the location is very windy you have to be careful as the solar panels can be blown away by the wind. In that case, you have to either fix the panels to the roofs or you can go for special installation equipment which is known as a ballast system. If you do not have to fix the panels to the roof the installation time and the installation cost also will reduce.

Flat roofs are usually made out of more durable materials than sloped roofs. So workers can move on the roof with more safety and roofs can easily endure the weight of the panels and installation systems. But as for the sloped roofs, flat roofs also should be inspected by a competent person before the installation.

When installing solar panels on the sloped roofs installers have to consider the roof angle and the roof orientation. But flat roofs are flexible. When installing on flat roofs you can install your panels to the optimum orientation and peak angles. When installing solar panels on flat roofs, installers use angled mounts to get more sunlight. But for some countries, the optimum angle cannot be achieved because the angle is limited to 10 – 20 degrees to optimize the space required. Flat roof panels require more space between raws to minimize the shading. Also, large panels require more ballast systems which will cost more.

What you should consider before installing solar panels on flat roofs?

Unlike sloped roofs when it comes to flat roofs there can other structures such as air conditioning units, pipes, vents, and many other structures. So the space available on the roof can be limited. As we stated earlier flat roof solar panels require more space between rows than sloped roof solar panels. So before installing solar panels you have to make sure there is enough space on the roof to fix the adequate amount of solar panels to get enough power. Also, you have to make sure that any of the solar panels will not be shaded from any of the outdoor structures. You have to clear all these points at the planning stage.

Also, you have to inspect the water-tightness of your roof. As we all know there is more probability of rainwater to be collected on flat roofs than sloped roofs. When you had fixed panels on the roof the this can be worsened. A huge amount of rainwater that is collected on roofs can result in water leakage into the building and cost a lot of damages to the interior. To avoid that we have to inspect the water-tightness of the roof and make sure there are ways to drain the collected water.

Not just that, you have to inspect the strength of your roof with the support of a competent person. The strength and the condition of your roof must be at the optimum level. The reason for this is unlike sloped roof solar panels, flat roofs need specially angled mounts, ballast system to work properly and safely. So to endure all these weights your roof must be in optimum condition.

What is the main risk for flat roof solar panels?

If the solar panels are free-standing solar panels wind is the main risk for them. If the wind speed is very high or if your area has frequent storms the solar panels may tend to fall off the roof or blew away by the wind. So to avoid that you have to follow one of the following methods. To secure the solar panels in place you can either fix them to the roof by penetrating which is followed when fixing solar panels on a sloped roof or you can steady the panels by using a ballast system or you can increase the weight of the panels using heavy concrete slabs.

Anyway, if the wind speed in your area is very high it is safe to fix the panels to your roof by penetrating it.

What is a “ballast system”?

Here the concrete blocks are placed throughout the solar panel/ solar panels arrays to secure them without penetrating the roof. This method is a good alternative to the penetration method as its costs more.

There are some instances that you cannot use the ballast system.

  • The strength of the roof is not enough to endure the weight of the system
  • There is not enough space between the panels and the roof.

How to install flat roof solar panels?

This process is not much different from the installation of sloped roof solar. The installation process is a lot easier on a flat roof.

First, you have to inspect your roof to make sure that your roof is in optimum condition. In this inspection roof strength, water leakage/ accumulation, space should be assessed.

Then you have to get the required permissions if needed.

Then you have to go through the planning process. In this step, the environment should be assessed also you have to decide how much power you hope to generate from the solar system. Such as the direction of the sunlight, wind speed, any objects that block the sunlight, etc. By this, you can decide the installation method, direction of the panels, angle of the solar panel mounts, and the specifications of the other components of the solar system (eg; inverter, battery, etc.) you needed, etc.

Then the installation process of the solar panels and the other parts of the system should be carried out.

Usually, solar panels are the only part of the solar system that will be installed outside. Other components will be installed in the covered area to protect them from extreme temperatures.

Solar panels can be either free-standing or fixed to the roof by various methods such as ballast system, penetration, etc.

Freestanding solar panels require only angled mounts and rails to place them securely with optimum angle. But these are not fixed to the roof. If you use a ballast system there will be the placement of concreter slabs throughout the rails to secure them by increase the weight. Then at last penetration method is the same as the method you used to fix the panels on sloped roofs. In this method, panels will be fixed to the roof by penetrating the roof.

Then finally the panels will be connected with the other components of the solar system.

Disadvantages or issues of using flat roof solar panels?

Even though there are many advantages of flat roof solar panels such as easy installations, there are many issues associated with them.

  • As we know we do not need to get any special planning permissions when installing sloped roof solar panels. But in some countries, flat roof solar panels require special planning permission. This law is only for domestic flat roofs not for non-domestic/ commercial buildings.
  • As mentioned before, the advantage of the flat roof solar panels is that we can fix them at an optimal angle. But this is not achievable due to some reasons such as optimization of the space and minimize the use of the ballast system. So due to those reasons, the angle is limited to 10 – 20 degrees which is not enough to receive a good amount of sunlight in some areas.
  • When compared to the sloped roof solar panels, flat roof solar panels require more space to produce the same amount of kW s as sloped roof solar panels.
  • Flat roof solar panels are prone to the accumulation of dust and other debris. Unlike sloped roof solar, these solar panels do not clean themselves even during the rainy season. So you have to clean the panels regularly to receive an adequate amount of sunlight.

Maintenance requirements of flat roof solar panels.

Maintenance of the flat roof solar panels is the same as for the sloped roof solar panels. The only difference is that the flat roofs require more regular cleaning than sloped roofs as these are unable to self-clean.

Also, you have to check the state and the water-tightness of your roof as there is more chance of water accumulation on the flat roof than on a sloped roof which will result in water leakages.